Shuttle Carrier Aircraft (SCA) 905 was manufactured as a passenger aircraft 747-100 for American Airlines in 1970 but acquired by NASA in 1974. By 1976, Boeing had heavily modified the aircraft by stripping its interior and strengthening the fuselage to support the weight of an 172,000 lb orbiter attached on top. The first-class seating remains for any passengers but all insulation was removed so it's very cold inside while airborne. This is the original plane responsible for all orbiter test flights in 1977, most ferry flights from Edwards Air Force Base back to Kennedy Space Center, and the final transports of the decommissioned orbiters to their new museum homes in 2012, a 30+ year span of service.